/*
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 * and open the template in the editor.
 */

package encrypt;

/**
 *
 * @author XuanHung
 */
public class DES implements BlockCipher
{
        private int[] workingKey = null;

        /**
         * standard constructor.
         */
        public DES()
        {
        }

        /**
         * initialise a DES cipher.
         *
         * @param encrypting
         *            whether or not we are for encryption.
         * @param key
         *            the parameters required to set up the cipher.
         * @exception IllegalArgumentException
         *                if the params argument is inappropriate.
         */
        @Override
        public void init(boolean encrypting, byte[] key)
        {
                this.workingKey = generateWorkingKey(encrypting, key, 0);
        }

        public String getAlgorithmName()
        {
                return "DES";
        }

        @Override
        public int getBlockSize()
        {
                return 8;
        }

        @Override
        public void transformBlock(byte[] in, int inOff, byte[] out, int outOff)
        {
                if (workingKey == null)
                {
                        throw new IllegalStateException("DES engine not initialised!");
                }

                desFunc(workingKey, in, inOff, out, outOff);
        }

        public void reset()
        {
        }

        /**
         * what follows is mainly taken from "Applied Cryptography", by Bruce
         * Schneier, however it also bears great resemblance to Richard
         * Outerbridge's D3DES...
         */

        static short[] Df_Key = { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32,
                        0x10, 0x89, 0xab, 0xcd, 0xef, 0x01, 0x23, 0x45, 0x67 };

        static short[] bytebit = { 0200, 0100, 040, 020, 010, 04, 02, 01 };

        static int[] bigbyte = { 0x800000, 0x400000, 0x200000, 0x100000, 0x80000, 0x40000, 0x20000, 0x10000, 0x8000,
                        0x4000, 0x2000, 0x1000, 0x800, 0x400, 0x200, 0x100, 0x80, 0x40, 0x20, 0x10, 0x8, 0x4, 0x2, 0x1 };

        /*
         * Use the key schedule specified in the Standard (ANSI X3.92-1981).
         */

        static byte[] pc1 = { 56, 48, 40, 32, 24, 16, 8, 0, 57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2,
                        59, 51, 43, 35, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 60, 52, 44, 36, 28, 20, 12,
                        4, 27, 19, 11, 3 };

        static byte[] totrot = { 1, 2, 4, 6, 8, 10, 12, 14, 15, 17, 19, 21, 23, 25, 27, 28 };

        static byte[] pc2 = { 13, 16, 10, 23, 0, 4, 2, 27, 14, 5, 20, 9, 22, 18, 11, 3, 25, 7, 15, 6, 26, 19, 12, 1, 40,
                        51, 30, 36, 46, 54, 29, 39, 50, 44, 32, 47, 43, 48, 38, 55, 33, 52, 45, 41, 49, 35, 28, 31 };

        static int[] SP1 = { 0x01010400, 0x00000000, 0x00010000, 0x01010404, 0x01010004, 0x00010404, 0x00000004,
                        0x00010000, 0x00000400, 0x01010400, 0x01010404, 0x00000400, 0x01000404, 0x01010004, 0x01000000, 0x00000004,
                        0x00000404, 0x01000400, 0x01000400, 0x00010400, 0x00010400, 0x01010000, 0x01010000, 0x01000404, 0x00010004,
                        0x01000004, 0x01000004, 0x00010004, 0x00000000, 0x00000404, 0x00010404, 0x01000000, 0x00010000, 0x01010404,
                        0x00000004, 0x01010000, 0x01010400, 0x01000000, 0x01000000, 0x00000400, 0x01010004, 0x00010000, 0x00010400,
                        0x01000004, 0x00000400, 0x00000004, 0x01000404, 0x00010404, 0x01010404, 0x00010004, 0x01010000, 0x01000404,
                        0x01000004, 0x00000404, 0x00010404, 0x01010400, 0x00000404, 0x01000400, 0x01000400, 0x00000000, 0x00010004,
                        0x00010400, 0x00000000, 0x01010004 };

        static int[] SP2 = { 0x80108020, 0x80008000, 0x00008000, 0x00108020, 0x00100000, 0x00000020, 0x80100020,
                        0x80008020, 0x80000020, 0x80108020, 0x80108000, 0x80000000, 0x80008000, 0x00100000, 0x00000020, 0x80100020,
                        0x00108000, 0x00100020, 0x80008020, 0x00000000, 0x80000000, 0x00008000, 0x00108020, 0x80100000, 0x00100020,
                        0x80000020, 0x00000000, 0x00108000, 0x00008020, 0x80108000, 0x80100000, 0x00008020, 0x00000000, 0x00108020,
                        0x80100020, 0x00100000, 0x80008020, 0x80100000, 0x80108000, 0x00008000, 0x80100000, 0x80008000, 0x00000020,
                        0x80108020, 0x00108020, 0x00000020, 0x00008000, 0x80000000, 0x00008020, 0x80108000, 0x00100000, 0x80000020,
                        0x00100020, 0x80008020, 0x80000020, 0x00100020, 0x00108000, 0x00000000, 0x80008000, 0x00008020, 0x80000000,
                        0x80100020, 0x80108020, 0x00108000 };

        static int[] SP3 = { 0x00000208, 0x08020200, 0x00000000, 0x08020008, 0x08000200, 0x00000000, 0x00020208,
                        0x08000200, 0x00020008, 0x08000008, 0x08000008, 0x00020000, 0x08020208, 0x00020008, 0x08020000, 0x00000208,
                        0x08000000, 0x00000008, 0x08020200, 0x00000200, 0x00020200, 0x08020000, 0x08020008, 0x00020208, 0x08000208,
                        0x00020200, 0x00020000, 0x08000208, 0x00000008, 0x08020208, 0x00000200, 0x08000000, 0x08020200, 0x08000000,
                        0x00020008, 0x00000208, 0x00020000, 0x08020200, 0x08000200, 0x00000000, 0x00000200, 0x00020008, 0x08020208,
                        0x08000200, 0x08000008, 0x00000200, 0x00000000, 0x08020008, 0x08000208, 0x00020000, 0x08000000, 0x08020208,
                        0x00000008, 0x00020208, 0x00020200, 0x08000008, 0x08020000, 0x08000208, 0x00000208, 0x08020000, 0x00020208,
                        0x00000008, 0x08020008, 0x00020200 };

        static int[] SP4 = { 0x00802001, 0x00002081, 0x00002081, 0x00000080, 0x00802080, 0x00800081, 0x00800001,
                        0x00002001, 0x00000000, 0x00802000, 0x00802000, 0x00802081, 0x00000081, 0x00000000, 0x00800080, 0x00800001,
                        0x00000001, 0x00002000, 0x00800000, 0x00802001, 0x00000080, 0x00800000, 0x00002001, 0x00002080, 0x00800081,
                        0x00000001, 0x00002080, 0x00800080, 0x00002000, 0x00802080, 0x00802081, 0x00000081, 0x00800080, 0x00800001,
                        0x00802000, 0x00802081, 0x00000081, 0x00000000, 0x00000000, 0x00802000, 0x00002080, 0x00800080, 0x00800081,
                        0x00000001, 0x00802001, 0x00002081, 0x00002081, 0x00000080, 0x00802081, 0x00000081, 0x00000001, 0x00002000,
                        0x00800001, 0x00002001, 0x00802080, 0x00800081, 0x00002001, 0x00002080, 0x00800000, 0x00802001, 0x00000080,
                        0x00800000, 0x00002000, 0x00802080 };

        static int[] SP5 = { 0x00000100, 0x02080100, 0x02080000, 0x42000100, 0x00080000, 0x00000100, 0x40000000,
                        0x02080000, 0x40080100, 0x00080000, 0x02000100, 0x40080100, 0x42000100, 0x42080000, 0x00080100, 0x40000000,
                        0x02000000, 0x40080000, 0x40080000, 0x00000000, 0x40000100, 0x42080100, 0x42080100, 0x02000100, 0x42080000,
                        0x40000100, 0x00000000, 0x42000000, 0x02080100, 0x02000000, 0x42000000, 0x00080100, 0x00080000, 0x42000100,
                        0x00000100, 0x02000000, 0x40000000, 0x02080000, 0x42000100, 0x40080100, 0x02000100, 0x40000000, 0x42080000,
                        0x02080100, 0x40080100, 0x00000100, 0x02000000, 0x42080000, 0x42080100, 0x00080100, 0x42000000, 0x42080100,
                        0x02080000, 0x00000000, 0x40080000, 0x42000000, 0x00080100, 0x02000100, 0x40000100, 0x00080000, 0x00000000,
                        0x40080000, 0x02080100, 0x40000100 };

        static int[] SP6 = { 0x20000010, 0x20400000, 0x00004000, 0x20404010, 0x20400000, 0x00000010, 0x20404010,
                        0x00400000, 0x20004000, 0x00404010, 0x00400000, 0x20000010, 0x00400010, 0x20004000, 0x20000000, 0x00004010,
                        0x00000000, 0x00400010, 0x20004010, 0x00004000, 0x00404000, 0x20004010, 0x00000010, 0x20400010, 0x20400010,
                        0x00000000, 0x00404010, 0x20404000, 0x00004010, 0x00404000, 0x20404000, 0x20000000, 0x20004000, 0x00000010,
                        0x20400010, 0x00404000, 0x20404010, 0x00400000, 0x00004010, 0x20000010, 0x00400000, 0x20004000, 0x20000000,
                        0x00004010, 0x20000010, 0x20404010, 0x00404000, 0x20400000, 0x00404010, 0x20404000, 0x00000000, 0x20400010,
                        0x00000010, 0x00004000, 0x20400000, 0x00404010, 0x00004000, 0x00400010, 0x20004010, 0x00000000, 0x20404000,
                        0x20000000, 0x00400010, 0x20004010 };

        static int[] SP7 = { 0x00200000, 0x04200002, 0x04000802, 0x00000000, 0x00000800, 0x04000802, 0x00200802,
                        0x04200800, 0x04200802, 0x00200000, 0x00000000, 0x04000002, 0x00000002, 0x04000000, 0x04200002, 0x00000802,
                        0x04000800, 0x00200802, 0x00200002, 0x04000800, 0x04000002, 0x04200000, 0x04200800, 0x00200002, 0x04200000,
                        0x00000800, 0x00000802, 0x04200802, 0x00200800, 0x00000002, 0x04000000, 0x00200800, 0x04000000, 0x00200800,
                        0x00200000, 0x04000802, 0x04000802, 0x04200002, 0x04200002, 0x00000002, 0x00200002, 0x04000000, 0x04000800,
                        0x00200000, 0x04200800, 0x00000802, 0x00200802, 0x04200800, 0x00000802, 0x04000002, 0x04200802, 0x04200000,
                        0x00200800, 0x00000000, 0x00000002, 0x04200802, 0x00000000, 0x00200802, 0x04200000, 0x00000800, 0x04000002,
                        0x04000800, 0x00000800, 0x00200002 };

        static int[] SP8 = { 0x10001040, 0x00001000, 0x00040000, 0x10041040, 0x10000000, 0x10001040, 0x00000040,
                        0x10000000, 0x00040040, 0x10040000, 0x10041040, 0x00041000, 0x10041000, 0x00041040, 0x00001000, 0x00000040,
                        0x10040000, 0x10000040, 0x10001000, 0x00001040, 0x00041000, 0x00040040, 0x10040040, 0x10041000, 0x00001040,
                        0x00000000, 0x00000000, 0x10040040, 0x10000040, 0x10001000, 0x00041040, 0x00040000, 0x00041040, 0x00040000,
                        0x10041000, 0x00001000, 0x00000040, 0x10040040, 0x00001000, 0x00041040, 0x10001000, 0x00000040, 0x10000040,
                        0x10040000, 0x10040040, 0x10000000, 0x00040000, 0x10001040, 0x00000000, 0x10041040, 0x00040040, 0x10000040,
                        0x10040000, 0x10001000, 0x10001040, 0x00000000, 0x10041040, 0x00041000, 0x00041000, 0x00001040, 0x00001040,
                        0x00040040, 0x10000000, 0x10041000 };

        /**
         * generate an integer based working key based on our secret key and what we
         * processing we are planning to do.
         *
         * Acknowledgements for this routine go to James Gillogly & Phil Karn.
         * (whoever, and wherever they are!).
         */
        protected int[] generateWorkingKey(boolean encrypting, byte[] key, int off)
        {
                int[] newKey = new int[32];
                boolean[] pc1m = new boolean[56], pcr = new boolean[56];

                for (int j = 0; j < 56; j++)
                {
                        int l = pc1[j];

                        pc1m[j] = ((key[off + (l >>> 3)] & bytebit[l & 07]) != 0);
                }

                for (int i = 0; i < 16; i++)
                {
                        int l, m, n;

                        if (encrypting)
                        {
                                m = i << 1;
                        }
                        else
                        {
                                m = (15 - i) << 1;
                        }

                        n = m + 1;
                        newKey[m] = newKey[n] = 0;

                        for (int j = 0; j < 28; j++)
                        {
                                l = j + totrot[i];
                                if (l < 28)
                                {
                                        pcr[j] = pc1m[l];
                                }
                                else
                                {
                                        pcr[j] = pc1m[l - 28];
                                }
                        }

                        for (int j = 28; j < 56; j++)
                        {
                                l = j + totrot[i];
                                if (l < 56)
                                {
                                        pcr[j] = pc1m[l];
                                }
                                else
                                {
                                        pcr[j] = pc1m[l - 28];
                                }
                        }

                        for (int j = 0; j < 24; j++)
                        {
                                if (pcr[pc2[j]])
                                {
                                        newKey[m] |= bigbyte[j];
                                }

                                if (pcr[pc2[j + 24]])
                                {
                                        newKey[n] |= bigbyte[j];
                                }
                        }
                }

                //
                // store the processed key
                //
                for (int i = 0; i != 32; i += 2)
                {
                        int i1, i2;

                        i1 = newKey[i];
                        i2 = newKey[i + 1];

                        newKey[i] = ((i1 & 0x00fc0000) << 6) | ((i1 & 0x00000fc0) << 10) | ((i2 & 0x00fc0000) >>> 10)
                                        | ((i2 & 0x00000fc0) >>> 6);

                        newKey[i + 1] = ((i1 & 0x0003f000) << 12) | ((i1 & 0x0000003f) << 16) | ((i2 & 0x0003f000) >>> 4)
                                        | (i2 & 0x0000003f);
                }

                return newKey;
        }

        /**
         * the DES engine.
         */
        protected void desFunc(int[] wKey, byte[] in, int inOff, byte[] out, int outOff)
        {
                int work, right, left;

                left = (in[inOff + 0] & 0xff) << 24;
                left |= (in[inOff + 1] & 0xff) << 16;
                left |= (in[inOff + 2] & 0xff) << 8;
                left |= (in[inOff + 3] & 0xff);

                right = (in[inOff + 4] & 0xff) << 24;
                right |= (in[inOff + 5] & 0xff) << 16;
                right |= (in[inOff + 6] & 0xff) << 8;
                right |= (in[inOff + 7] & 0xff);

                work = ((left >>> 4) ^ right) & 0x0f0f0f0f;
                right ^= work;
                left ^= (work << 4);
                work = ((left >>> 16) ^ right) & 0x0000ffff;
                right ^= work;
                left ^= (work << 16);
                work = ((right >>> 2) ^ left) & 0x33333333;
                left ^= work;
                right ^= (work << 2);
                work = ((right >>> 8) ^ left) & 0x00ff00ff;
                left ^= work;
                right ^= (work << 8);
                right = ((right << 1) | ((right >>> 31) & 1)) & 0xffffffff;
                work = (left ^ right) & 0xaaaaaaaa;
                left ^= work;
                right ^= work;
                left = ((left << 1) | ((left >>> 31) & 1)) & 0xffffffff;

                for (int round = 0; round < 8; round++)
                {
                        int fval;

                        work = (right << 28) | (right >>> 4);
                        work ^= wKey[round * 4 + 0];
                        fval = SP7[work & 0x3f];
                        fval |= SP5[(work >>> 8) & 0x3f];
                        fval |= SP3[(work >>> 16) & 0x3f];
                        fval |= SP1[(work >>> 24) & 0x3f];
                        work = right ^ wKey[round * 4 + 1];
                        fval |= SP8[work & 0x3f];
                        fval |= SP6[(work >>> 8) & 0x3f];
                        fval |= SP4[(work >>> 16) & 0x3f];
                        fval |= SP2[(work >>> 24) & 0x3f];
                        left ^= fval;
                        work = (left << 28) | (left >>> 4);
                        work ^= wKey[round * 4 + 2];
                        fval = SP7[work & 0x3f];
                        fval |= SP5[(work >>> 8) & 0x3f];
                        fval |= SP3[(work >>> 16) & 0x3f];
                        fval |= SP1[(work >>> 24) & 0x3f];
                        work = left ^ wKey[round * 4 + 3];
                        fval |= SP8[work & 0x3f];
                        fval |= SP6[(work >>> 8) & 0x3f];
                        fval |= SP4[(work >>> 16) & 0x3f];
                        fval |= SP2[(work >>> 24) & 0x3f];
                        right ^= fval;
                }

                right = (right << 31) | (right >>> 1);
                work = (left ^ right) & 0xaaaaaaaa;
                left ^= work;
                right ^= work;
                left = (left << 31) | (left >>> 1);
                work = ((left >>> 8) ^ right) & 0x00ff00ff;
                right ^= work;
                left ^= (work << 8);
                work = ((left >>> 2) ^ right) & 0x33333333;
                right ^= work;
                left ^= (work << 2);
                work = ((right >>> 16) ^ left) & 0x0000ffff;
                left ^= work;
                right ^= (work << 16);
                work = ((right >>> 4) ^ left) & 0x0f0f0f0f;
                left ^= work;
                right ^= (work << 4);

                out[outOff + 0] = (byte) ((right >>> 24) & 0xff);
                out[outOff + 1] = (byte) ((right >>> 16) & 0xff);
                out[outOff + 2] = (byte) ((right >>> 8) & 0xff);
                out[outOff + 3] = (byte) (right & 0xff);
                out[outOff + 4] = (byte) ((left >>> 24) & 0xff);
                out[outOff + 5] = (byte) ((left >>> 16) & 0xff);
                out[outOff + 6] = (byte) ((left >>> 8) & 0xff);
                out[outOff + 7] = (byte) (left & 0xff);
        }
}

